On 05/01/2012 04:41 AM, Johannes Weiner wrote:> The readahead code searches the page cache for non-present pages, or> holes, to get a picture of the area surrounding a fault e.g.>> For this it sufficed to rely on the radix tree definition of holes,> which is "empty tree slot". This is about to change, though, because> shadow page descriptors will be stored in the page cache when the real> pages get evicted from memory.>> Fortunately, nobody outside the readahead code uses these functions> and they have no internal knowledge of the radix tree structures, so> just move them over to mm/readahead.c where they can later be adapted> to handle the new definition of "page cache hole".>> Signed-off-by: Johannes Weiner<hannes@cmpxchg.org>